EAF-LF-VD全流程生产T91钢的洁净度研究  

Investigation on Cleanliness of T91 Steel in EAF-LF-VD Process

作　　者：郭宝奇 包燕平[1] 张乐辰[1] 张超杰[1] 

机构地区：[1]北京科技大学钢铁冶金新技术国家重点实验室,北京100083

出　　处：《铸造技术》2015年第4期935-939,共5页Foundry Technology

基　　金：国家自然科学基金资助项目(51274029)

摘　　要：通过对T91钢种的EAF-LF-VD全流程的取样分析,研究了钢中氧氮含量的变化情况,以及夹杂物的转变过程。结果表明:LF至VD氧含量呈逐步下降趋势,在LF炉中出现增氮现象,VD破空后氮含量下降,然后进行增氮。热力学分析得出全流程中前期适合脱氮,后程适合增氮。夹杂物的数量在LF炉与VD炉中分别有下降的趋势,轧材中夹杂物数量升高。LF进站主要为形状不规则的Al2O3,LF精炼结束时钢中夹杂物多为圆形,内部为先析出的Mg O-Al2O3,外部为Ca O-Al2O3。VD过程中夹杂物尺寸有所下降,主要成分均为Ca O-Al2O3-Mg O。轧材中夹杂物多为大尺寸的条状Al2O3夹杂物,与不规则的链状Al2O3-Mg O尖晶石类夹杂物,该类夹杂物主要来源于浇注过程的二次氧化,对轧材危害较大。Through the analysis of the samples of T91 steel in the process of EAF-LF-VD, the changes of oxygen and nitrogen content in the steel as well as the transformation of inclusions were investigated. The results show that oxygen content presents gradual declined trend from LF to VD, and nitrogen content increasing in LF process and decreasing in VD and supplement at end of VD. According to thermodynamic analysis, it is appropriate for denitrification at earlier stage and adding nitrogen at the final phase of the whole process. Quantity of inclusions experiences reducing trend in both LF and VD, while amount of inclusions in rolled steel increasing. At the beginning of LF, inclusions are Al2O3 of irregular shape, and at the endpoint of LF, inclusions are transformed into the circular ones, of which inner part is MgO-Al2O3 and periphery is CaO-Al2O3. Dominant composition of inclusions is CaO-Al2O3-MgO and dimensions of inclusions declining. The large-dimension inclusions in rolled steel is mainly comprises of strip-shape Al2O3 and irregular Al2O3-MgO spinel inclusion.

关 键 词：T91钢 洁净度 氧 氮 夹杂物 

分 类 号：TF76[冶金工程—钢铁冶金]